dokeeffe

Hi Steve, Will the mentioned engine pass Cal smog requirements in a '95 car. Thanks for sharing!

Steve Weiner-Rennsport Systems

With an exhaust system that has cats, yes,..it can be made to pass the sniffer test.

Physically, likely not since it looks different from OEM.

mr_bock

I just saw this thread and read all the way through. Very interesting...

Shortly after buying my 993 with 20k miles on it. I felt that the car need more hp. I went with a TPC supercharger. They (TPC) weren't too far from where I lived in Virginia. I spent about $15k for the kit and install. Dyno was 202 at the rear wheels and 322 rwhp after!!! About 20k miles later, the clutch was starting to slip. I pulled the engine and trans and had Mike Bruns rebuild the engine and LSD. They did a great job. I added a lightweight flywheel and heavy duty clutch. The car is great fun!!!!!

By the way, shameless plug, this car is for sale in the classifieds in this Forum. My interests have shifted.

callipygian 911

Steve's being humble here. He and Jeff Gamroth are among the best in the business at building high-powered, naturally-aspirated flat 6 engines. I wanted a 3.8L that was first and foremost as reliable as a factory fresh engine, if not moreso. There is no one else I'd trust with my hard-won money in pursuing such a build. While there are plenty of good engine builders in this country, there are few with the combined expertise and class of these gentlemen. And, similar to the Porsche company, these guys never overestimate the horsepower and torque figures of their builds. There is only so much air that can be pushed through these engines which, I understand, gives rise to inherent limitations with natural aspiration. 400 hp engines and above does seem a bit too good to be true. I'm confident time will bear all this out.

A notable datapoint is Ed Pink's 4.0L build for Singer, which reputedly puts out 390 hp. This is likely close to the upper limit, folks.

http://singervehicledesign.com/4-lit...-lusciousness/

trophy

Agreed to a point, any engines built around stock heads will have an upper limit of around or just under 400hp, (thats exactly where my 4.0l engine sits.) The top end for those with the bank roll to invest in aftermarket heads (9M, Elite, Extreme etc.) looks like the 450 mark, but that is close to an additional $12k to $15k investment on top of everything else.

What is very clear with these engines, HP is VERY VERY expensive...

Steve Weiner-Rennsport Systems

Oh no,...not at all.

It simply takes the correct combination of parts and components to go well over 400 BHP.

Its simply not inexpensive to do this.

callipygian 911

Huh. I guess time has already borne this out, then.

Steve, does going with these trick heads necessitate Motec to run and/or higher compression and increased RPM? Or just Motec? Or just compression? Or both?

If so, would these changes detrimentally affect long-term engine durability for those of us that are concerned with durability?

Just wondering ... for a friend. Yeah, that's right ... a friend.

<furtively checks financial statements>

dokeeffe

Hi Steve,
Considering passing Cal smog, would your built engine be preferred in an obdi or obdii car? thanks

Steve Weiner-Rennsport Systems

Hi Josh,

Trick heads are required for HP levels over 360 BHP. Motec is needed to take advantage of the increase in airflow at all RPM's. Remember, these heads require different intake, camshafts, and exhaust to make the expenditure worthwhile and those such engines will not be OBD-II compliant.

Engine durability and longevity are most impacted by CR and maximum operating RPM. Keep the CR compatible with pump gasolines and the max RPM under 7300 and it will last as long as the original engine can.

Steve Weiner-Rennsport Systems

Any Motec-equipped engine will never be OBD-II compliant so a '95 or earlier is preferable (unless one lives in a state where smog tests are not required any longer).

For CA cars, we stick with the original intake system and the Motronic engine management for this express purpose. One simply limits any modifications to cams & displacement.

callipygian 911

Great information, Steve. Thank you. This is relevant to those dreaming about or planning a big engine build.

JM993

For those of us in CA, is it possible to run ITBs via the stock Motronic for um, "testing" purposes? Then switch to a different engine management system for "off road" use if you catch my drift. Let's assume this would be for an OBD-1 car.

callipygian 911

I believe it is, as I discussed this possibility briefly with Steve and Jeff when I visited their shop.

erikerik

Reviving this thread... anyone here have recent dyno charts of their 4.0L’s?

doc_porsche

would love to hear more about this given that prices of turbo are out of reach to a lot of us